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blue Carthew - Alderson Trail


8.8 mile 14.2 kilometer point to point
76% Runnable


Ascent: 1,273' 388 m
Descent: -3,411' -1,040 m
High: 7,671' 2,338 m
Low: 4,260' 1,298 m


Avg Grade: 10% (6°)
Max Grade: 40% (22°)


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Trail shared by Joan Pendleton

A remote trail through gorgeous mountain scenery; meadows, wildflowers, peaks, turquoise lakes, fir forests, & creeks.

Joan Pendleton

Features Lake · River/Creek · Views · Waterfall · Wildflowers · Wildlife


The Carthew - Alderson Trail starts at Summit Lake. Summit Lake can be reached by Summit Lake Trail, that starts at Cameron Lake.

Summit Lake to shoulder of Mt Carthew:
At Summit Lake, the Carthew - Alderson Trail heads away from Summit Lake, going through meadows and thinly forested sections. It begins to climb gradually to a ridge in the distance, the shoulder of Mt Carthew. As it climbs, the trees give way to low bushes, and a sea of peaks to the south comes into view, including Chapman Peak and Mt Custer. Soon, the trail begins to climb switchbacks on the bare slope of the shoulder of Mt Carthew. The views get better and better! A few dark turquoise lakes come into view at the base of the peaks. These are the inaccessible North Lakes in Glacier National Park. The switchbacks end on the shoulder of Mt. Carthew.

Shoulder of Mt Carthew to Carthew Lakes:
The shoulder of Mt Carthew is the high point of Carthew - Alderson Trail. From the shoulder of Mt Carthew, in the direction ahead, one can now see the three Carthew Lakes below. Beyond them in the distance are the prairies of Alberta. The descent from here towards the Carthew Lakes is on a talus slope. The talus is made of small rocks and large gravel. The descent is gradual enough so that there is low risk of losing one's footing. Just above the first Carthew Lake, there is a snow patch to cross, even in late summer.

Carthew Lakes:
The Carthew Lakes are three beautiful, turquoise blue, alpine lakes. They are nestled in the valley between Mt Carthew and the shoulder of Mt Alderson. They are surrounded by talus slopes, alpine meadows, and snow patches. The trail follows the shoreline of the two larger Carthew Lakes and is flat here.

Carthew Lakes to Alderson Lake:
Veering away from the middle Carthew Lake, the trail begins a steep descent, as it heads to Alderson Lake. The descent begins over rocky and then bush-covered terrain. As altitude is lost, the bushes become larger and short trees begin to dominate. The trees get taller, and one is in a thin fir forest when they reach Alderson Lake. Alderson Lake is a sub-alpine lake, surrounded by walls of Mt Alderson on the sides opposite the trail.

Alderson Lake to Waterton Townsite:
Leaving Alderson Lake, one quickly finds themselves in a thick fir forest, with Carthew Creek at the bottom of the steep hillside to the left of the trail. The trail gradually descends into Waterton Townsite for the last four miles.

This is a segment of the GDT (Great Divide Trail):

Flora & Fauna

Fir forests, sub-alpine meadows, alpine meadows, wildflowers, bare scree and rock.

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We need help with the following missing trail information:

Need to Know, Dogs Allowed, Runner Notes


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